Electrical conductivity and defect structure of manganese oxide doped yttria-stabilized zirconia (3 mol%Y2O3)

The oxygen partial pressure dependence of the electrical conductivity of (ZrO2-3 mol%Y2O3)(1-x)(MnOt)(x) (x=0, 0.030, 0.052, 0.076) has been measured at temperatures from 1273 to 1373 K. In the range of oxygen partial pressures from 1 x 10(5) to 1 x 10(-5) Pa, the conductivity increased with decreasing pressure, and at less than 1 x 10(-5) Pa, the conductivity was constant. The conductivity considerably decreased with dissolution of only 3.0 mol%MnOt, but it gradually increased over 5.2 mol%MnOt. The conductivity was thought to be equal to the ionic conductivity due to oxygen ions. A defect structure model has been proposed and the apparent mobility of the oxygen ion has been calculated under the condition that the valence state of Mn ions is +3 and +2 at P-O2 value of 1 x 105 Pa and 1 x 10(-13) Pa, respectively. The oxygen partial pressure and the MnOt concentration dependence of the conductivity was discussed based on the defect structure model and the mobility.